Langue: en

Version: October 2007 (MeeGo - 06/11/10)

Section: 7 (Divers)


bugle-extoverride - hide OpenGL extensions from an application


 filterset extoverride
     version "1.5"
     disable "all"
     disable "extension"
     enable "extension"


The extoverride filter-set modifies the version and extension strings to hide driver capabilities from the application. The primary use is to test an application to ensure that it works correctly on drivers that do not offer these capabilities.

Apart from modifying these strings, a warning is printed to the log if any function from one of these extensions is called.



Sets a new value for GL_VERSION. However, if the true value is lexicographically smaller than this value, the true value is used.

disable "all"

By default, extensions are exposed unless explicitly disabled. This option reverses the behaviour to hide all extensions that are not explicitly enabled.

disable "extension"

Hides the named extension from the application. A warning is printed if the extension was not known at the time bugle was compiled; in this case it will still be hidden, but there will not be any warning if it is used anyway.

enable "extension"

Like the disable option, but enables an extension when the default is disabled.


Warnings are only printed if functions from the disabled extensions are called. At present, no warning will be printed if tokens from those extensions are passed (which is difficult to determine, since multiple tokens may share the same numeric value). Furthermore, some extensions alter semantics without explicit functions or tokens, such as GL_ARB_texture_non_power_of_two; no warnings are issued if these extensions are used.

Also note that extension loader libraries may interfere with the warning mechanism. For example, GLee uses wrappers that cause illegal function calls to be silently ignored.


bugle is written and maintained by Bruce Merry.


bugle(3), bugle-log(7), bugle-showextensions(7)